# Glossary > Definitions of the physics, regulatory, measurement and health terms used throughout the dataset. - Canonical URL: https://emfbase.com/glossary - JSON: https://emfbase.com/api/glossary - CSV export: https://emfbase.com/export/glossary.csv - Records: 30 ## Records - [Attention value and quality objective](https://emfbase.com/glossary/attention-value): Italy's two precautionary legal tiers below the exposure limit: the attention value applies where people spend four or more hours a day, the quality objective applies outdoors in busy areas. - [Averaging time](https://emfbase.com/glossary/averaging-time): Regulatory limits apply to an average: 30 minutes for the general public under FCC and ICNIRP rules, 6 minutes for occupational exposure. - [Beamforming](https://emfbase.com/glossary/beamforming): 5G massive-MIMO antennas steer energy toward active users rather than radiating uniformly, so exposure is intermittent and direction-dependent. - [Building biology (Baubiologie) and SBM](https://emfbase.com/glossary/building-biology): A German-origin discipline whose SBM testing methodology grades sleeping areas into precautionary bands far below regulatory limits. - [Dirty electricity](https://emfbase.com/glossary/dirty-electricity): High-frequency harmonics and transients riding on mains wiring, typically from dimmers, switch-mode supplies and inverters. Not a term used in any exposure standard. - [Duty cycle](https://emfbase.com/glossary/duty-cycle): The fraction of time a transmitter is actually radiating — the reason a peak reading and a time-averaged exposure can differ by a factor of a hundred or more. - [EHS (electromagnetic hypersensitivity)](https://emfbase.com/glossary/ehs): Symptoms attributed by the affected person to EMF exposure; recognised as real symptoms by WHO, without a demonstrated causal link to field exposure in blinded studies. - [EIRP / ERP](https://emfbase.com/glossary/eirp): Transmitter power multiplied by antenna gain: the figure that, with distance, determines free-space power density. - [ELF (extremely low frequency)](https://emfbase.com/glossary/elf): Fields below about 300 Hz, dominated by the 50 or 60 Hz power supply and its harmonics. - [Far field and near field](https://emfbase.com/glossary/far-field): Beyond roughly a wavelength from an antenna the field behaves as a propagating wave and inverse-square estimates apply; closer than that they do not. - [Faraday cage](https://emfbase.com/glossary/faraday-cage): A continuous grounded conductive enclosure. Effective in principle, and in practice limited entirely by its apertures. - [IARC Group 2B](https://emfbase.com/glossary/group-2b): 'Possibly carcinogenic to humans' — a statement about how strong the evidence is, not about how large any risk is. - [Installation limit value](https://emfbase.com/glossary/installation-limit-value): A precautionary legal limit applied to a single installation at sensitive locations, used in Switzerland and set far below the general exposure limit. - [Inverse-square law](https://emfbase.com/glossary/inverse-square-law): In the far field, doubling the distance quarters the power density: the cheapest and most reliable mitigation available. - [ISO/IEC 17025 accreditation](https://emfbase.com/glossary/iso-17025): Accreditation of a laboratory as competent for a named measurement method — the credential regulators require, as distinct from any personal certification. - [Milligauss (mG) and microtesla (µT)](https://emfbase.com/glossary/milligauss): The two units for power-frequency magnetic fields: 1 µT = 10 mG, so 0.4 µT = 4 mG. - [MPE (maximum permissible exposure)](https://emfbase.com/glossary/mpe): The FCC's term for the enforceable exposure limit expressed as field strength or power density. - [Net current (wiring error)](https://emfbase.com/glossary/net-current): When the current flowing out on a circuit does not return on the same cable, the imbalance radiates a magnetic field across the whole building. - [Nocebo effect](https://emfbase.com/glossary/nocebo-effect): Genuine symptoms produced by the expectation of harm rather than by the exposure itself — the inverse of the placebo effect. - [Non-ionizing radiation](https://emfbase.com/glossary/non-ionizing-radiation): Electromagnetic radiation whose photons lack the energy to remove electrons from atoms — everything below ultraviolet, including all EMF discussed on this site. - [Non-thermal effect](https://emfbase.com/glossary/non-thermal-effect): A proposed biological effect at exposure levels too low to cause measurable heating; the central claim of precautionary guidelines and the central objection of regulators. - [Precautionary principle (as applied to EMF)](https://emfbase.com/glossary/precautionary-principle): The basis for values set below the level justified by established effects, such as the Swiss installation limits and building-biology bands. - [Provocation study](https://emfbase.com/glossary/provocation-study): An experiment in which a volunteer is exposed to a real or sham field without knowing which, to test whether exposure triggers symptoms or can be detected. - [Reference level vs basic restriction](https://emfbase.com/glossary/reference-level): ICNIRP's two-tier structure: basic restrictions are the dosimetric limits that matter biologically; reference levels are the externally measurable proxies derived from them. - [RF (radiofrequency)](https://emfbase.com/glossary/rf): Fields from about 100 kHz to 300 GHz, the range used by all wireless communication. - [SAR (specific absorption rate)](https://emfbase.com/glossary/sar): Watts absorbed per kilogram of tissue, the dosimetric basis of phone compliance testing — 1.6 W/kg over 1 g in the U.S., 2 W/kg over 10 g under ICNIRP. - [Shielding effectiveness (dB)](https://emfbase.com/glossary/shielding-effectiveness): Attenuation expressed logarithmically: 10 dB removes 90% of power density, 20 dB removes 99%, 30 dB removes 99.9%. - [Thermal effect](https://emfbase.com/glossary/thermal-effect): Tissue heating from absorbed RF energy — the established mechanism that RF exposure limits are set to prevent, with a safety margin. - [Uncontrolled vs controlled environment](https://emfbase.com/glossary/uncontrolled-environment): The North American equivalent of the general-public and occupational tiers: 'uncontrolled' means people who are not aware of their exposure and cannot act on it. - [µW/m², mW/m² and mW/cm²](https://emfbase.com/glossary/power-density-units): Three units for the same RF quantity, spanning ten orders of magnitude: 1 mW/cm² = 10 W/m² = 10,000 mW/m² = 10,000,000 µW/m².